A coldroom complex recently installed at the Fisheries Research Board of Canada, Freshwater Institute laboratory at Winnipeg features several design aspects that are considered novel. These include foamed-in-place urethane insulation, two alternating R-502 refrigeration systems incorporating automatic safety switch-over and adjustable defrost, "straight-line" pneumatic temperature control, hot gas bypass control, and a master panel. The facility combines a cold laboratory at +2 C, a long-term storage room at −37 C, a small anteroom at −26 C, and a room containing eight 10.0-ft3 precise temperature cabinets at −40 C. Room temperature variation is ±0.25 degrees C during steady state conditions. Temperature rise during daily defrosting is less than 2 degrees C for a duration of 1 hr.